Turbine Assembly for use in a Downhole Pulsing Apparatus

Abstract

A downhole pulsing apparatus having a tubular housing, a first valve assembly positioned in the housing, first and second turbine stages each comprising a stator and a rotor positioned in the housing below the first valve assembly and a second valve assembly positioned in the housing. There is a tubular mandrel connected for rotation of the rotors of the turbine stages and to a second valve assembly. The first valve assembly includes a valve element which is movable between a first position wherein pressurized fluid flow entering the housing is directed to the first turbine assembly, and a second position wherein the fluid flow is directed primarily axially through the apparatus so as to partially bypass the first turbine stage.

What is claimed is: 
     
         1 . A downhole pulsing apparatus comprising:
 an elongate tubular housing having a first upper end and a second lower end;   a first valve assembly positioned in said housing proximal said first end, said first valve assembly comprising:
 a valve element reciprocally mounted in said housing, said valve element comprising an elongate stem having a first end forming a head portion, a second end, and a longitudinally extending bore, a radial bleed port formed in said body proximal said heat portion, a first radial aperture formed in said stem proximal said second end; 
 a first compression spring disposed in said housing for biasing said valve element to a first position; 
 a first chamber in surrounding relationship to said stem, said bleed port providing open communication between said chamber and said bore in said stem; 
   a first turbine stage comprising:
 a first stator assembly positioned in said housing below said first valve assembly, said first stator assembly comprising a first stator body having a through bore forming a first stator cavity and a plurality of radially outwardly extending angled vanes attached to said first stator body, a first stator annular flow path being formed between said first stator body and said housing; 
 a first rotor assembly positioned in said housing below said first stator assembly, said first rotor assembly comprising a first rotor body having a first central flow path in open communication with said through bore and a first rotor annular flow path in open communication with said first stator annular flow path, a plurality of radially outwardly extending angled first rotor vanes connected to said first rotor body and disposed in said first rotor annular flow path, whereby fluid flow from said first stator annular flow path impinges on said first rotor vanes; 
   a tubular mandrel having a first end, a second end, and an axial passageway therethrough, said passageway being in open communication with said central flow path through said first rotor assembly, said first end of said mandrel being connected to said first rotor assembly for rotation therewith;   a second turbine stage positioned in said housing below said first turbine stage, said second turbine stage comprising a second stator body having a central bore therethrough, said second stator body being fixed to said housing, said second turbine stage further comprising a second rotor body having a central bore therethrough, said mandrel extending through said central bore in said second stator body and said second rotor body, said second rotor body being connected to said mandrel for rotation therewith;   a second valve assembly disposed in said housing and connected to said second end of said mandrel, said second valve assembly being movable between a first partially open position and a second fully open position in response to rotation of said mandrel,   whereby pressurized fluid acting on said valve element in a first position initially flows through said annular flow path of said first turbine stage, continued application of said pressurized fluid moving said valve element to a second position compressing said first spring and forcing fluid in said first chamber through said bleed port into said bore and moving said first aperture in register with said stator cavity, thereby diverting at least a portion of said pressurized fluid flow from said first turbine stage to said first stator cavity.   
     
     
         2 . The apparatus of  claim 1 , wherein said valve assembly further comprises an elongate tube having a first tube end and a second tube end, said valve element being reciprocally received in said elongate tube. 
     
     
         3 . The apparatus of  claim 2 , wherein said head portion of said valve element comprises a first radially outwardly extending flange and an annular axially facing piston surface forming a mouth of said bore. 
     
     
         4 . The apparatus of  claim 3 , wherein there is a second annular radially outwardly extending flange formed on said stem and axially spaced from said first flange, an annular space in surrounding relationship to said stem being formed in said tube between said second flange and said first stator body. 
     
     
         5 . The apparatus of  claim 4 , wherein there is a spring stop disposed in said annular space and a second compression spring disposed between said second flange and said spring stop. 
     
     
         6 . The apparatus of  claim 4 , wherein there is an axially extending passage formed through said second flange. 
     
     
         7 . The apparatus of  claim 6 , wherein there is an annular seal between said second flange and said tube, a radially innermost annular seal between said sleeve and said tube, and a radially outermost annular seal between said sleeve and said tube, a variable volume chamber being formed between said sleeve and said second flange, said axially extending passage in said second flange being in open communication with said variable volume chamber whereby as said valve element moves to said second position, pressure in said variable volume chamber is reduced as said variable volume chamber increases in volume. 
     
     
         8 . The apparatus of  claim 4 , wherein there is a second radial aperture formed in said stem between said first aperture and said first end of said stem, at least a portion of said second aperture being in register with said annular space wherein said valve element is in said second position. 
     
     
         9 . The apparatus of  claim 1 , wherein said first rotor body comprises a central core portion in surrounding relationship to said central flow path and therein an outer first rotor sleeve, a first rotor annulus being formed between said central core portion and said first outer sleeve, said first rotor vanes being disposed in said first rotor annulus and interconnected to said central core portion and said first outer sleeve. 
     
     
         10 . The apparatus of  claim 9 , further comprising a plurality of angled ports in said central core portion said angled ports providing open communication between said central flow path and said first rotor annulus. 
     
     
         11 . The apparatus of  claim 1 , wherein said second valve assembly comprises first and second valve members having first and second axial flow paths, respectively, said first valve member being operatively connected to said mandrel for rotation therewith, said second valve member being fixed, rotation of said first valve member varying the alignment of said first and second openings between a minimum open area and a maximum open area to permit an intermittently fluid flow pulse through said second end of said housing. 
     
     
         12 . The apparatus of  claim 11 , wherein said second axial flow opening in said second valve member is generally crescent shaped when viewed in plan view. 
     
     
         13 . The apparatus of  claim 12 , wherein said generally crescent shaped opening forms the mouth of a passageway extending through said second valve member, said second valve member comprising a disc shaped plate having an upper surface proximal said first valve member. 
     
     
         14 . The apparatus of  claim 13 , wherein said first valve member comprises a second disc shaped plate. 
     
     
         15 . The apparatus of  claim 13 , wherein said second valve mandrel comprises a disc shaped plate. 
     
     
         16 . The apparatus of  claim 11 , wherein there is a terminal turbine stage comprising a terminal rotor assembly fixed to said housing and having a central bore therethrough, said mandrel extending through said central bore of said terminal stator body and a terminal stator assembly, said terminal stator assembly being operatively connected to the second end of said mandrel. 
     
     
         17 . A turbine assembly comprising:
 a tubular housing having a first end and a second end;   a valve assembly positioned in said housing proximal said first end;   a first turbine stage positioned in said housing between said first valve assembly and said second end of said housing, said first turbine stage having a first axial flow path and a first annular flow path;   a second turbine stage positioned in said housing between said first turbine stage and said second end, said second turbine stage having a second axial fluid flow path and a second annular fluid flow path;   a tubular drive shaft connected to first and second rotor assemblies of said first and second turbine stages for rotation therewith, said drive shaft having an axially extending flowway therethrough, said first and second axial fluid flow paths and said axially extending flowway providing a central fluid flow path through said turbine;   said first valve assembly being movable from a first position wherein pressurized fluid introduced into said first end of said housing flows through said first annular fluid flow path and a second position wherein at least a portion of said pressurized fluid flowing through said first annular fluid flow path is diverted to said axial fluid flow path.   
     
     
         18 . A downhole pulsing apparatus comprising:
 an elongate tubular housing having a first upper end and a second lower end;   a first valve assembly positioned in said housing proximal said first end, said first valve assembly comprising:
 a valve element reciprocally mounted in said housing for movement between a first axial position and a second axial position, said first valve assembly including a modulator, said modulator delaying movement of said valve element from said first position to said second position; 
   a first turbine stage comprising:
 a first stator assembly positioned in said housing below said first valve assembly, said first stator assembly comprising a first stator body having a through bore, a first stator annular flow path being formed between said first stator body and said housing; 
 a first rotor assembly positioned in said housing below said first stator assembly, said first rotor assembly comprising a first rotor body having a first central flow path in open communication with said through bore and a first rotor annular flow path in open communication with said first stator annular flow path; 
   a tubular mandrel having a first end, a second end, and an axial passageway therethrough, said passageway being in open communication with said central flow path through said first rotor assembly, said first end of said mandrel being connected to said first rotor assembly for rotation therewith;   a second turbine stage positioned in said housing below said first turbine stage, said second turbine stage comprising a second stator body having a central bore therethrough, said second stator body being fixed to said housing, said second turbine stage further comprising a second rotor body having a central bore therethrough, said mandrel extending through said central bores in said second stator body and said second rotor body, said second rotor body being connected to said mandrel for rotation therewith;   a second valve assembly disposed in said housing and connected to said second end of said mandrel, said second valve assembly being movable between a first partially open position and a second fully open position in response to rotation of said mandrel,   whereby pressurized fluid acting on said valve element in said first axial position initially flows through said annular flow path of said first turbine stage, continued application of said pressurized fluid moving said valve element to said second axial position, thereby diverting at least a portion of said pressurized fluid flow from said annular flow path through said first turbine stage to said through bore through said first stator cavity.